Turbomachine compressors, and turbojet stators in particular, may include a variable-pitch guide vane stage arranged on a casing. The position of the vanes is controlled by a rotary ring that is connected to each guide vane by a link. Thus the angle of attack of the vanes can be controlled as a function of flight conditions by a control system that drives the rotation of the ring. The link of the invention can be used with advantage in the control system.
More generally, many kinematic systems use a link to transmit a driving rotary movement to a driven rotary movement. In prior art systems this link has a constant length.
Links of variable length are also known in the art but the length of the link can be modified only when the link is not operating.
In certain transmission systems it is necessary to be able to apply a relatively complex relationship governing the transmission from one rotary movement to another rotary movement.
An object of the present invention is to provide a link the length whereof may be varied when the link is operating.
It is equally beneficial for a link of the above kind to be fitted into the kinematic system as a replacement for a link of fixed length without having to modify the rest of the kinematic system.